土壤生物多样性与微量气体(CO_2、CH_4、N_2O)代谢

Soil biodiversity and trace gases (CO_2, CH_4, N_2O) metabolism: a review

土壤生物是重要的基因库 ,土壤生物多样性是全球生物多样性的重要组成部分。土壤生物是C、N地球化学过程 (土壤库 )的驱动者 ,调控微量气体代谢。在微量气体代谢中 ,土壤微生物具有直接的作用。真菌、CH4 生成菌、CH4 氧化菌、硝化菌以及反硝化菌等是调控微量气体代谢的关键生态功能类群。由于相对大的体积和强大的酶化学分解作用 ,真菌通常主导枯枝落叶的分解活动。“通气—厌气”界面是微生物群落的活跃区域 ,易发生微量气体代谢。“有机—无机”过渡层、水生植物根际区、土壤动物肠道系统是典型的微量气体代谢界面。土壤动物对微量气体代谢的作用通常为前期的和间接的 ,并且又是重要的。节肢动物 (白蚁 )和环节动物 (蚯蚓 )是分别代谢CH4 和N2 O的两个关键性生态功能类群。在研究土壤生物多样性及其对微量气体代谢的作用方面 ,由于土壤生态系统的复杂性 ,需综合传统微生物实验技术与现代同位素技术和分子生物学技术。我国缺乏研究土壤生物多样性及其对微量气体代谢影响的实质性工作 ,有必要开展这方面的研究。

Soil biota is an important gene library and forms a major part of global biodiversity. Soil biota drive the cycling of soil C and N biogeochemistry and influence trace gases metabolism. Soil microorganisms exercise direct effects on trace gases metabolism. Fungi, methanogens, CH 4-oxidizing bacteria, nitrifiers, and denitrifiers are the key types of communities regulating trace gases metabolism. Fungi often dominate degradation activities in litter due to their large individual body and strong enzyme chemical degradation abilities. “Oxic-anoxic” interfaces are active habitats for microorganisms and easily influence trace gases metabolism. “Organic-inorganic” layers, the rhizosphere of hydrophytes, and soil faunal intestines are the typical interfaces for trace gases metabolism. Soil fauna are pioneers for litter degradation and show indirect effects on trace gases metabolism, and these effects are very important. Arthropods (e.g. termites) and annelid (e.g. earthworms) metabolise CH 4 and N 2O, respectively. Since the soil ecosystem is complicated, it is necessary to develop an integrated technique comprising microbiology, stable isotope and molecular biology for studying soil biodiversity and its effects on trace gases metabolism. Research on soil biodiversity and its relationship to trace gases metabolism urgently needs to be developed in China.